"The sexual assault which led to the arrest took place early Friday morning on the South Side, when Neal made a traffic stop on a 19-year-old woman. Neal was in full uniform, in a marked patrol car, and on-duty when the sexual assault occurred," San Antonio Police spokesman Sgt. Javier Salazar said in a statement.

"The 40-year-old officer is an 11-year veteran and is assigned to South Patrol on the overnight shift. He has been placed on Administrative Leave."

Police say Neal led the woman to the back of his patrol car, where he handcuffed her and assaulted her.

The on-board cameras in Neal's vehicle were not working. But GPS showed his police cruiser was stopped at a particular spot for 18 minutes. It's the same spot that the victim alleged the assault took place.

Neal was charged with felony sexual assault, and was out on bond Monday. He has been placed on paid administrative leave, as per department policy.

Chief William McManus called Neal's alleged conduct "unthinkable."

"I'm outraged," he told reporters. "It's a punch in the eye to the police department."

Another woman made a similar claim about Neal a few years ago but refused to testify, McManus said. The department is reaching out to her again.

Neal was previously disciplined for violating department policy by dating an 18-year-old woman in the Explorers program, the police chief said. The program introduces young people to careers in law enforcement.